The Google notification may have an error in it. The new version is given as 7.0.517.44 for Windows, Mac, Linux and Chrome Frame. My own Chrome system says it's running 7.0.517.41 and two commenters to the announcement post say the same of their own installations. This number is so close that I assume .41 is the update.

All vulnerabilities are rated "High" which, in Google's vulnerability rating guidelines, means that information has been compromised or code executed in the sandbox. A critical vulnerability in Chrome requires that code execute out of the sandbox, and these are rare. Google gave out $7,500 to researchers who reported these bugs to them.